Telescope



-Aug 19 1924.,

Filed Aug. 26

Patented: Aug. 19, 1924.

UNITED STATES PATENT OFFICE.

HEINRICH ERFLE, OF JENA, GERMANY, ASSIG NOR TO THE FIRM CARL ZEISS, OF JENA, GERMANY.

TELESCOPE.

Application filed August 28, 1922. 4 Serial No. 584,562.

To all whom it may comer n:

Be it known that I, HEINRICH ERFLE, a citizen of the German Empire, and residing at Jena, Germany, have invented a new and 5 useful Telescope, of which the following is a specification. I Y

The present invention relates to a telescope having a prism system which contains. two lateral boundarysurfaces, parallel to each other and an optional number of reflecting surfaces, inclined to these boundary surfaces. According to the invention there is disposed a changing device in order to bring the prism system from one position in which it divides the telescope axis into two parts, which embrace an angle deviating from zero, into a second position in which its lateral boundary surfaces are perpendicular to one of those two parts of the telescope axis,

i. e. in which the prism system onl acts as a plane-parallel glass plate. This a ords the possibility of passing over from the one position of the prism system to the other without substantially causing the prism system to change its location. Hence, it is not necessary to fix on the telescope a prism casing which is considerably larger than the prism system itself.

I If the prism system be disposed on the side of the li ht entrance of the telescope, it is, e. g. possi 1e to afford to an observer the look-out-in two different directions in succession. Another advantageous constructional form of the invention results if one of the reflecting, surfaces of the prism system be devised in such a way that it reflects only one part of the light, whilst it allows to pass the otherone, if therefore half of this reflecting surface be silvered and if the i prism system be disposed in such a way that in its one position it divides the ray pencil system emanating from the telescope objective into two partial systems, each of which is transmitted to one of two oculars. By

bringing the prism system with the aid of the I aforesaid changing device into its second position in which its lateral boundary surfaces are perpendicular to that part of the telescope axis which lies in front of the prism system, it is possible, on the oculars being suitably disposed, to dispense with the observer at the one ocular and'to place the full luminosity at the disposal of the observer at the other ocular. In that case the prism is suitably formed by a pentagonal prism, of the two reflecting surfaces of which the one is so devised as to reflect only one part of the rays impinging on it whilst it allows to pass the other part, a glass wedge being cemented on this reflecting surface, the outer surface of which is parallel to'thefirst named reflecting surface of the pentagonal prism.

In order to bring the prism system from one position into the other, it is generally necessary to impart to it a rotation about 90 and a displacement in the direction of the axis of rotation. These two motionsmay be performed by scre'w motion. In the case of large dimensions of the prism system a singlerota'tion may be sufficient.

Fig. 1 shows as the first constructional example of the invention the head of an upright telescope in a section through the optical axis of the instrument. Fig. 2 shows as thesecond constructional example of the invention a telescope in a section through its optical axis.

The constructional example shown in Fig. 1 is to afford to an observer a look-out in the lateral and in the height direction in succession. A collective lens member a, two dispersive lens members a and an and a singly reflecting prism 6 form the objective system of the telescope. The lens members are all rigidly disposed within the telescope casing c, the arrangement being such that the two look-out'axes embrace an acute angle. The prism b is disposed in a mount 03 which is provided with two bear-F ing pivots, the one of which, d, is cylindrical and supported within the casing a, whilst the other one, 03 is devised as a hollow pivot and guided on a pivot e, rotatably supported within the casing and having a rectangular cross section. Besides, the axis f-ofthe cylindrical pivot d coincides with" the axis of rotation of the pivot e,

thereby lying in the plane determined by the perpendicular'ly the telescope axis in the notch in, both oculars o and o are H two look-out axes and being directed perpendieularly to the telescope axis. At its outer circumference the ho low pivot d is provided with a screw-groove d in which engages a pin 0 fixed on the casing c. In order to bring the prism from the position shown in the drawing by continuous lines, in which it mediates the lateral look-out, into its second position of use shown in the drawin by dotted lines, in which it affords the 100 -out upwards, the pivot 0 must be rotated about 90 by meansof a milled head a, whereby the prism undergoes, on the one 'hand, owing to the straight guide of the hollow pivot 01 on the pivot e, a rotation about'90 and, on the other hand, owing to the pin 0 engaging in the groove d, a displacement in the direction of the axis of rotation. The prism is protected from incidental rotations by a spring f, which is fixed on the casing c and which in the position of the prism, corresponding to the lateral look-out, engages in a notch e and in the osition of the rism, corresponding to the ook-out upwar s, in a notch e of the milled. head e.

In the constructional example shown in Fig. 2 there are fixed within a' casin 9 an objective h, a collective lens 11 an a reversing lens 7'. Directly behindthis reversing; lens there is a separating prism which consists of a pentagonal prism deflectin by and of a glass wedge Z cemente to this prism. The angle of this wedge is so chosen that the outer surface of t face of the prism. The surface 70 of the prism k is silvered all overfwhilst of the surface k of the prism 70, upon which the glass wedge l is cemented, only a number ofstripsof uniform width are silvered which are ac arated by uncoated strips of the same .wi th. The separating prism 10, l is supported rotatabl within the casing 9 about an axis Y. which a .the prism being rotatable by 90 by means of 'a milled head m. The latter is provided with two notches m and m and, in addition, there is fixed on the casing g a springn which is capable ofwmeshing with one =of the two notches and then protects the separat' Behlnd t e separating prism k, I there are prism from incidental rotations.

disposed two oculars o and o in such a way that theaxis of the ocular 0' coincides with the axis X-X and the axis of the ocular o with the axis Y-Y. a

If the separating prisnrk, 1' assumes the position shown in the drawingiby continuous lines in which the spring n'engages operative. If, however, the se arating pl ism occupies the position which 13 shown 0 wedge is parallel to the entrance surby dotted lines and in which the spring at flection on the said reflecting surfaces into two parts embracing an angle and in the other one of which the prism systems lateral boundary surfaces being perpendicular to one of these two parts of the telescope axis so as to be traversed by the rays passing through the telescope, and the said telescope further containing a changing device adapted to bring the said prism system from the one position into the other.

p 2. In a telescope twooculars, a prism system, containing two lateral boundary surfaces parallel to each other and a number of reflecting surfaces perpendicular to these boundary surfaces, one of the said reflecting surfaces beingdevised in such a way as to reflect only one part of the light, whilst it allows to pass the other, the said prism system being adapted to occupy two positions, in the one of which the ray pencil system emanating from the telescope objective is divided into two artia'l systems, each of which is transmitted oculars and in the other one of which its lateral boundary surfaces are perpendicular to that part of the telescope axis which lies in front of the said prism system, and the to one of the twosaid telescope further containing a changparallel to the other reflecting sur ace, the

said pentagonal rism being rotatable about an axis perpen lcular to that part of the telescope axis, which lies in front of the said prism, and parallel to a plane per-' pendieular to the *said reflecting surfaces, the prism thereby being adapted to occupy two ositions, inthe one of which the ray penci system penetrating the telescope ob- ]ective is divided into two artial systems, each, of which is transmitte to one of the two oculars, the axis of the one of the vice adapted to rotate the pentagonal prism oculars colnciding with the said part of the about its axis of rotation. telescope axis, and in the other position of which the lateral boundary surfaces of the HEINRICH ERFLE. separating prism are perpendicular to the Witnesses: said part of the telescope. axis, and the said 7 CANE KRiiGER, v

telescope further containing a changing de-- FRITZ SANDER. 

